To invoke the rights under due process principles,9 a party must establish the existence of a protected interest. The plaintiffs claim that they have a protected “property” in*17terest under the Boston rent control ordinance.10 Their argument is based on the provision that a rented unit continues to be controlled, despite a change in occupancy after January 1, 1976, until a certificate of decontrol is issued. That argument overlooks the fact that after January 1, 1976, any person commencing a tenancy in Boston was on at least constructive notice (see Parsons v. Lenox, 228 Mass. 231, 235 [1917]; National Fireproofing Co. v. Kelley, 253 Mass. 344, 345-346 [1925]) that the premises could be decontrolled, which event he could not prevent except in unusual circumstances, i.e. forced or constructive eviction of the prior tenant (see n.5).11 The plaintiffs were not warranted in expecting to be protected by rent control. See Lotto v. Commonwealth, 369 Mass. 775, 778 (1976); Regents of State Colleges v. Roth, 408 U.S. 564, 578 (1972). The temporary existence of rent control protections following a vacancy does not give rise to an entitlement to continuing protection. That temporary continuance of controls is to maintain the controlled rent in effect while the board carries on its responsibilities of administrative oversight of the decontrol process. The reason for the exercise of such administrative oversight is to remove any incentive a landlord might have to cause or create a vacancy by improper means in order to secure the decontrol of the rental unit. Whatever benefit the new tenant derives from the delay is in the nature of a windfall.